Yeah Banane. has it right with skin sizing, though I will say when you have wider skis like that, you already have quite a lot of skin surface area. There is plenty to grip the snow, especially when it's softer, so you don't really need wall to wall coverage. Some skin companies have actually removed a strip of "skin" from the center of their wider skins to reduce weight. The uphill grip is basically from your toes to the back of the ski. I got 125mm skins for my bentchetlers(144.5/123/136.5) because I don't really plan on skinning on any gnarly steep ice or anything like that. You can typically get away without the whole tip being covered and save a bit of money on narrower skins.